1. Field of the Invention
The present invention relates to a display apparatus and an adjustment mechanism.
2. Description of the Related Art
Recently, display apparatuses such as self-luminous type display apparatuses, for example, plasma display apparatuses, and backlight type liquid crystal display apparatuses having light sources divisionally provided for the respective areas have been in widespread use. In a liquid crystal display apparatus, since the backlight emits light with uniform luminance and generates heat uniformly, exterior parts and the like covering the liquid crystal panel absorb heat near the peripheral portion of the liquid crystal panel. Therefore, the temperature of the peripheral portion of the liquid crystal panel becomes lower than that of the central portion, resulting in the occurrence of temperature irregularity (temperature distribution) inside the liquid crystal panel. Note that since the liquid crystal forming the liquid crystal panel changes in response speed with changes in temperature, image quality deteriorates due to color irregularity caused by temperature irregularity in the liquid crystal panel.
A technique for homogenizing the temperature in a liquid crystal panel has therefore been proposed in Japanese Patent Laid-Open No. 6-281905. Japanese Patent Laid-Open No. 6-281905 discloses a structure which includes a flat cooling passage between a liquid crystal panel and an incident-side polarizing plate to form an airflow rate distribution such that the airflow rate at the middle portion becomes maximum and the airflow rate at the two side portions becomes minimum in the widthwise direction of the cooling passage.
Liquid crystal panels decrease in response speed with decreases in temperature. In order to solve this problem, Japanese Patent Laid-Open No. 2002-311416 has proposed a liquid crystal display apparatus that measures (monitors) the temperature of the liquid crystal panel and controls the driving of a cooling fan or backlight in accordance with the temperature. Japanese Patent Laid-Open No. 2002-311416 discloses a technique to raise the temperature of the liquid crystal panel by increasing the current in the backlight if the temperature of the liquid crystal panel is low, and to lower the temperature of the liquid crystal panel by cooling it with a cooling fan if the temperature of the liquid crystal panel is high.
On the other hand, there is known a technique of uniformly cooling the overall liquid crystal panel of a self-luminous type display apparatus including no backlight.
According to Japanese Patent Laid-Open No. 6-281905, however, in a self-luminous type display apparatus or a backlight type liquid crystal display apparatus having light sources divisionally provided for the respective areas, it is very difficult to sufficiently homogenize the temperature of the display panel (for example, maintain the temperature of the display panel within an allowable range). In a display panel, the amounts of heat generated differ in the respective areas in accordance with the image displayed on the display panel. According to Japanese Patent Laid-Open No. 6-281905, however, the airflow rate distribution formed in the cooling passage remains unchanged (that is, the airflow rate distribution is constant in spite of the fact that the amount of heat generated in the display panel varies for each area). In Japanese Patent Laid-Open No. 6-281905, therefore, it is likely that an optimal airflow rate distribution is not formed for the generation of heat in the display panel.
In Japanese Patent Laid-Open No. 2002-311416, when the temperature of the display panel changes (in order to homogenize the temperature of the display panel), since the luminance of the backlight changes, the image (image quality) displayed on the display panel may deteriorate.